Vibrator system



y 1966 G. L. MALAN 3,249,338

VIBRATOR SYSTEM Filed April 23, 1965 /0/ m2 ,1. Is/

' INVENTOR.

650266 4. MAZAA/ /60 fig: ATTOln/EYS'.

' size used in the concrete is relatively small.

United States Patent 3,249,338 VIBRATOR SYSTEM George L. Malan, 560 E. Rowland St., Apt. G-3,

Covina, Calif. Filed Apr. 23, 1965, Ser. No. 450,294 Claims. (Cl. 259-1) This invention relates to means for mounting vibrators in order to improve versatility of the vibrators.

This application is a continuation-impart of applicants co-pending application, Serial No. 257,436 filed February 11, 1963, entitled, Vibrator Mounting Means, now Patent No. 3,180,624 (issued April 27, 1965) 259-1'.

Hand-held vibrators of the type ordinarily used in highway and dam construction weigh in the range between about to 100 lbs., and have diameters between about 1 /2 and 8 inches. The vibrator unit is usually attached rigidly to a handle. The handle is manipulated by one or more men to thrust the vibrator into the concrete mass in order to vibrate it and thereby to settle and distribute it.

In light construction, such as building foundations and walls, pillars, and the like, vibrators are used whose diameter and weight are quite small. They can easily be manipulated by one person. Furthermore, the concrete used in such work is usually quite plastic, and the rock In view of this, there is no particular difiiculty involved in the present technique of manipulating vibrators on light construction. One man can readily handle the vibrator, and the jobs are small and do not take a very long time. It therefore appears that present vibration techniques are generally suitable for this class of concrete work.

However, in heavy concrete work, such as in the building of dams, powerhouses, and other massive structures, it is customary to utilize rubble rock in the concrete, which rock may have dimensions on the order of 6-8 inches. Furthermore, theconcrete used is usually very stilt, the

water content being held to a minimum. In this class of construction, it is still common practice for the vibrators to be manipulated by hand, even though their weights and diameters are quite large. This is heavy, hard work, because the vibrators are heavy, and the end loads which must be exerted to get the vibrator into the concrete may at times be quite large. Often more than one man is required to do the job.

A similar end-load problem arises in the earth compaction field, wherein the vibrator must be axially forced into the earth. Many persons now regard end-thrust means as a necessity to force these vibrators into the medium to be compacted or distributed.

There is still another field in which vibrators have begun to show usefulness. and water wells, wherein the unbalanced lateral vibrations of the vibrator serve to fracture, or to aid in flushing out formations adjacent to the well casing. In these applications, there is a substantial unbalanced end load required to force the vibrator into a deep well and to keep it there. Also, there is the problem of resisting high ambient pressures within the well.

As end loads increase, there arises the need for means other than men to hold the vibrator while it operates. In a well, a pipe string can do the job by virtue of its own weight. However, there is no similar equipment available on a dam face, nor in a region of earth to be compacted. Accordingly, some base, such as a vehicle needs to be provided, which can give support and, preferably,

will also be mobile.

It is desirable that the vibratory energy go into the surroundingregion, and not into the supporting means, when the vibrator is working. Transmission of vibratory forces to men or to machinery is both wasteful and This is in the treatment of oil I 3,249,338 Patented May 3, 1966 damaging. Men, while manipulating the handle of a small vibrator, are able to act as a loose link. This is not as true when they handle the larger vibrators. For mechanical bases such as vehicles, loose links must be especially provide-d. It is an object of this invention to provide a coupling which accomplishes this objective by providing a link of variable rigidity.

Both greater and lesser rigidity is at times necessary in either the sleeve-type or the ball-type joint. F or example, when ambient pressures or end loads on sleeve-type joints become too great, there is a tendency of the sleeve to collapse either axially or laterally. This, of course, disables it. The sleeve must be self-supported and then, should a heavy end load have to be overcome axially, it should be more rigid in order to transmit the force. If it is merely to deflect and slip past an obstruction, it must be less rigid.

The situation is generally similar with ball joints, except that heavy end loads may tend to jam the joint elements together and make the joint totally rigid. This tendency must be overcome to maintain any flexibility at all.

In summary, a couplings rigidity needs to be variable to overcome certain problems likely to be met in some of its uses, and both greater and lesser rigidity may be called for. Many of the conditions calling for this use must be met without the users being aware of the instant necessity, such as that occasioned by the ambient pressure in a deep well. For this reason, it is desirable to make certain of the responses automatic, and this is an optional object of the invention.

The invention includes a joint formed by inherently flexible means, such as a sleeve or a ball joint which means joins a handle and a vibrator on a concentric central axis, together with pressure means adapted to control the flexibility of the joint.

According to a preferred but optional feature of the invention, the pressure means is controlled by a signal derived from axial thrust means. The said axial thrust means is adapted to force the vibrator axially into a resistive environment.

According to still another optional feature of the invention, the flexible means comprises a ball joint, and the pressure means comprises a pair of opposed, inversely related pressure pads which tend to center the. ball in the joint.

The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, in which:

FIG. 1 is a side elevation, partly in cross-section and partly in schematic notation, showing an embodiment of the invention;

FIG. 2 is a cross-section taken at line 2-2 of FIG. 1;

FIG. 3 shows a portion of FIG. 1 in another position;

FIG. 4 is an axial cross-section of another embodiment of the invention; and

FIG. 5 is an axial cross-section showing a modification of the device of FIG. 4.

FIG. lshows the presently preferred embodiment of the invention mounted to a vehicle 10. An axial thrust means 11 comprises a hydraulic cylinder 12, piston rod 13, and a piston 13a to which the rod is mounted. Supply ports 13b and center the cylinder on opposite sides of the piston. The cylinder is mounted to the vehicle by hinge 14. Rod 13 is attached to a thrust collar 15 outside the cylinder.

A direction control means 16 is also attached to the vehicle by a hinge 17. It comprises a cylinder 18 and a piston-driven, extensible and retractible piston rod 19.

hinge 20. The axes of all of the hinges are parallel.

A vibrator 21 includes a housing 22 having a neck end 23. Any conventional type of vibrator may be used.

' Vibrators such as those shown in United States Letters Patent to Malan, Nos. 2,187,088; 2,743,090; and 2,891,775 are suitable. Vibrator 21, and each of the examples, are provided with central pressure ports and co-axial outer exhaust ports.

A handle 30 includes a thrust collar 31 which abuts and is attached to thrust collar 15. The handle includes a central flexible pressure line 32 adapted to be connected to a source of pressure through line 33 and to the central pressure port of the vibrator. Pressure line 32 is surrounded by a co-axial exhaust line 34 and to an exhaust line 35. 'The handle also includes a reduced neck end 36..

The lower end of pressure line 32 in FIG. 1 may be considered as the inlet pressure port of the vibrator. Coaxial region 34a (of the exhaust line 34) in housing 22,, adjacent to the vibrator, may be considered a the outlet (exhaust) port of the vibrator.

A coupling generally designated by numeral 37 cornprises a tube 38, which surrounds and is attached to neck ends 23 and 36 by bands 39, 40 or any other suitable means. The tube spaces the neck ends apart along axis 41 of the vibrator, and joins them. The central pressure line is not intended to provide any structural. support between the handle and the vibrator. The only substantial structural support for the vibrator from the handle is exerted by tube 38. The coupling is inherently flexible, but stiff enough to resist bending. It may, for example, have an axial length of about 7 inches with a free length between the neck ends of about 3 to 4 inches. For a 6- inch diameter vibrator operating at about 1000 p.s.i.g., the wall thickness of this tube may be about A to 1 inch and may conventiently be made of fairly hard rubber. The inside free length of the tube is exposed to exhaust pressure from the vibrator. This pressure tends to thrust the handle and vibrator apart, placing the tube in axial tension. It also tends to apply expansive forces thereon.

The properties and dimensions of the tube will be selected to resist too-easy bending, but still to be inherently flexible. Axis 41 is the common axis of the handle, couplingv and vibrator when they are at rest. The thrust control means and the direction control means are adjusted to exert axial thrust to force the vibrator in the desired direction. The vibrator is placed in operation by applying pressure to pressure line 33. In operation the vibrator exerts unbalanced lateral forces. Obviously, there will be some side deflection of the vibrator relative to the axis of the handle whenever the vibrator operates, because the coupling is inherently flexible, and this is desirable in order to. dissipate the major proportion of the vibratory energy into the surroundings, thereby wasting a minimum of such energy in shaking the vehicle. The inherent flexibility of the tube is lessened by axial tension to which the tube is subjected by the fluid pressure, and this property of the coupling can be utilized to stiffen the coupling when stiffness is desired. Conversely, lessening of the axial tension by an axial compression force lessens the rigidity, and this property can be utilized to render the coupling less rigid when more flexibility is desired.

One control system capable of both automatically and manually regulating the flexibility, and. conversely the rigidity, of the sleeve-type coupling is shown in FIG 1. A

closed, hermetically-sealed reservoir 50 has a pressure dome 51 which is connected to a first-chamber 52 of a differential-pressure accumulator 53. The second chamber 54 of accumulator 53 has a lesser cross-sectional area than the first chamber. A differential piston 55 is slidably fitted in the two chambers. A vent port 56 is formed through the accumulator wall just above the region traversed by the lower portion of the piston to vent the same.

The hydraulic system is closed, and not vented to atmosphere in order that theexhaust pressure (back pressure) may be regulated. Liquid 57 does not entirely fill the pressure dome, but leaves a region therein above the liquid, which is occupied by a gas. This region is connected to the first chamber of the accumulator. The purpose of the differential pressure accumulator is tostep down the pressure from a pump 58.

Constant delivery pump 58' withdraws liquid from the reservoir and pumps it from line 59 to line 60, line 60 being connected to line 3. A throttle valve 61 is provided in line 60. A constant speed motor 62 drives pump 58. This motor and pump deliver a predetermined volume of liquid per unit time, but the absolute pressure at which the liquid is delivered depends upon the back pressure in the system and; on the demand of the vibrator.

Line 60 is side-tapped by line 63 which discharges into one port of a selector valve 64. Line 65 connects another port of the selector valve to the. second chamber of the accumulator.

Line 66 interconnects still another port 66a of the selector valve to the reservoir through a bleed-type regulator 67 and a pump 68.. The selector valve can be set to disconnect all of its lines from each other, or to connect lines 63 and 65 or lines 65 and 66.

Line 69 connects exhaust line 35 to the reservoir. A variable restrictor 70may, if desired, be placed in line 69.

FIG. 4 illustrates the broad scope of the invention, as applicable to flexible couplingsv in general, whether the coupling is also elastic or not, so long as the coupling can be placed in axial tension by internal forces, which tension is opposable by axial compressive forces on the structure. Handle 30 and vibrator 21 are shown joined by a coupling 100, which is a ball joint. Pressure line 32 and exhaust line 34 passthrough the coupling.

The handle neck has. been modified by a ball 101, and the vibrator neck has been modified by a seat 102. A retainer 103 has a seat 104 which is threaded onto the vibrator neck, the ball being trapped between seats 102 and 104. This ball joint is inherently flexible around the center of theball. .In accordance with conventional construction,- a very smallclea'rance is left between the seats and the ball topermit. these surfaces to be lubricated. Conventional seals (not shown) may be provided between the seats and .ball surfaces to minimize leakage and con fine the lubricant, if desired.

An additional control over the joint of FIG. 1 can be obtained with the'use of the hydraulic circuit provided for thrust means 11. When binding end loads which might axially collapse the sleeve, or such high ambient pressures as might cave it in, must be resisted, thisis readily accomplished by raising the back pressure inside sleeve 38. Because both of these pressures show asend loads which must be overcome by thrust means 11,; it is possible to use the pressure on the thrust side of piston 13 as a signal to control the back pressure.

This is readily accomplished in a simple hydraulic control system as shown, as well as in more sophisticated systems. A pump draws hydraulic fluid 126 from a reservoir127. and boosts it through a throttle valve 128 to a 4-way selector valve 129, which selectively interconnects ports 13b and 13c to pressure line 130 or to an exhaust line 131. Of course, there is a neutral, off, position where both ports are closed from both lines. Exhaust fluid is returned to reservoir. Thus, throttle valve 128 governs the pressure to cylinder 12, and selector valve 129 directs the flow.

Signal line 132 is teed on from port 13b (which is on the thrust side of the piston), and extendsto a pressure regulator valve 133 in line 69. When control of back pressure as a function of axial thrust is not desired, regulator 133 is bypassed, or opend wide so it has no elfect.

This regulator is a simple pressure-diaphragm operated type. When pressure in line 132 goes up because of an increase in the axial thrust of means 11, regulator 133 is set to proportionally increase the back pressure in exhaust line 34. Thus regulator 133 regulates the pressure upstream of itself by acting as a throttle.

vide a reference pressure drop.

and the other decreases.

I optionally be provided to eliminate any risk of the balljoints binding up with increasing end loads. Note in FIG. that pressure in region 34 exerts an unbalanced 'force to the left on ball member 154, which is identical in shape and purpose to ball member 101. This means that the optional control means including pressure regulator 133 may be used in this embodiment as well-as in FIG. 1. However, when this control is not used, it

may be that sufficient centering force may not, in some environments be developed to keep the ball joint from binding. This can be overcome as shown in FIG. 5 by providing socket members 150, 151 with pressure pads 152, 153, respectively, which are at axially opposite sides of the center of ball member 154. The joint has a central axis 155.

The pads extend peripherally around axis 155 on the inside surface of the socket members. O-ring seals 156 isolate the pads from the surroundings. Pad 152 includes a peripheral pressure groove 158, exhaust groove 157, and reference surface 159. Pad 153 includes a peripheral pressure groove 160, exhaust groove 161, and reference surface 162.

A pump 163 (or even line 132, should it be desired to'use axial thrust forces as both a controlling force and controlling signal), discharges to pressure grooves 158 and 160 through orifices 164, 165, respectively. These orifices prevent the excessive loss of pressure in one pressure groove when pressure drops in the other and pro- Exhaust grooves 157 and 161 discharge to reservoir.

In both pads, flow is from the pressure to the exhaust groove over the respective reference surface. The reference surfaces are spherical fragments spaced from the ball by a reference distance whenthe centers of the ball and of the socket are coincident.

When the ball center moves axially relative to the center of its socket, then one reference distance increases The pressure increases at the pad where the distance is lesser, and decreases at the padwhere the distance is greater. This constitutes an unbalanced axial force which tends to return the ball toward the centered position, and thereby resists binding.

An optimum pressure supply system for FIG. 5 constitutes a pair of constant delivery pumps, one for each pad,

and in some installations, it will be worth the greater expense, for inthis casethere is a sharper relationship between the change in pressure and in reference distance. The selection of the circuitry will be determined at least in' part by the type of use intended.

sentially as positive-displacement motors. They will operate at a frequency determined by the rate of flow. The

absolute working pressure may vary. The pressure drop across a vibrator (that is the differential pressure between thepressure and exhaust lines) will increase as the load on the vibrator increases, and decrease as the load decreases and this, of course, affects the rate of flow. In

general, the lightest load in vibrators of this class will occur when the vibrator is running free in the air, and the heaviest load occurs when the vibrator is placed in a stiff, but still plastic medium, such as stifffluid concrete of low water content or nearly-compacted earth.

places a heavier load on the motor and its energy supply. The pressure generated by the pump will automatically rise as the motor increases its labor to put out the same volume against a greater resistance.

In a closed unvented system such as that shown in FIG. 1, the inlet pressure differs from reservoir pressure by an increment equal to the pressure drop across the vibrator plus the line losses. It follows that exhaust pressure relative to atmosphere can be regulated in order to control the pressure inside the coupling, which in turn raises the inlet pressure, but leaves the differential pressure between inlet and exhaust lines substantially unaffected. The pressure in the exhaust line thereby is variable with the load on the vibrator, and by the back pressure exerted from the reservoir. This latter provides means for controlling the flexibility and rigidity of the coupling. The control of back pressure by the thrust means has already been described. This latter control can be eliminated or disabled by by-passing or opening wide regulator 133.

Assume that pump 58 is running so as to deliver its prescribed volume, and that the throttle valve is wide open. The selector valve is set to connect lines 33, 60 and 65. This sets the reservoir pressure (which is the pump inlet pressuregand coupling pressure) at a lower valve than pump outlet pressure, this value'being determined by the ratio between the cross-sectional areas of the chambers. Thus, the back pressure in the reservoir and on the exhaust side of the vibrator, is establishe by the output pressure of the vibrator.

Assuming that the vibrator is running at a light load, the pressure difference between lines 32 and 34 is at a value toward its minimum, and the system adjusts itself accordingly, the pump output pressure also being at a working minimum to supply the pressure differential required. Because the differential is small, the pump output pressure is relatively small, and so is the pressure inside the coupling. Now when the vibrator is placed under a heavier load, the differential pressure across it, that is, the working pressure to force a constant volume of fluid per unit time, through the vibrator increases. Therefore the output pressure of the pump increases, a heavier load being placed on motor 62.

An increase in the output pressure raises the accumulator, reservoir, and coupling pressure, and the pump output pressure adjusts itself accordingly. The important result of this is an increase in the back pressure in the coupling.

A similar result could have been secured by adjusting restrictor 70, but it is uneconomical to use restrictor valves in this type of circuit merely to control pressures, because of the amount of work it takes to pump fluid through them. The accumulator adjusts the pressures without wasting energy. Therefore, restrictor 70 is not to be preferred, and, if present, is usually kept wide open. It is an adjustable throttle set to one adjustment, as contrasted with the continually changing adjustment of regulator 133.

When the coupling pressure increases, its stiffness increases, and it will be noted that this occurred in the above example when the load increased. An increased load might reflect the meeting of an end-loading obstruction of the type a strong axial push could overcome, such as might be encountered in shoving the vibrator into earth to be compacted, or into a high ambient pressure like that found inside an oil well. This coupling, which is relatively flexible in normal running operation, becomes stiflt'er with increased load, which is one useful way to operate it.

Another mode of operation is to preset the reservoir or back pressure to some value, such as by connecting lines and 66, and using pump 68 and bleed-type regulator 67 to maintain a constant pressure in line 65. The regulator shown maintains pressure in line 66, and discharges excess fluid through line 71 to the reservoir. With this arrangement, the coupling has a preset pressure level, and

any end load will oppose this level, thereby rendering the coupling more, instead of less, flexible, as shown in FIG. 3. The difference here is that the elongating force is constant and can be overcome by the compressive force to render the coupling more flexible, while in the previous example, an increasing load made the coupling more rigid. Thus, the coupling is made versatile to cope with various situations. When a more rigid coupling is needed in order to axially pierce a region, it is available. When a more flexible coupling is needed to provide for side flailing, that too is available. In both arrangements, a normal 'flexi bility is available for normal operations.

When the ball joint is provided, the results are the same. The additional or lesser loadings result in greater or lesser flexibility. Furthermore, the elongating forces tend to overcome the compressive forces, thereby enabling lubrication to reach the adjacent surfaces, thereby overcoming the cause of many ball joint failures, i.e., lack of lubrication at strongly forced-together abutting, relatively sliding surfaces. The ball joint is, therefore, a mechanical equivalent of the flexible but elastic tube in many important respects.

The additional versatility of operation derived from controlling back pressure as a function of another operating property-end thrust pressure, for example, and of the supplementary ball centering means of FIG. have already been described.

While the examples have been directed toward the use of liquids for power and control, the use of gases is analogous and obvious to persons skilled in the art.

The term vehicle as usedherein is not intended to be limited to any particular class of mobile element. In fact, the vehicle might be skid-mounted, wheel-mounted, or trackwrnounted, or mere-1y stand on a base. The term vehicle is intended to define a supporting structure which is subject to being moved, either under its power, or by being lifted or shoved around by any means, without limitation as to the exact nature of the supporting means or of the motive means.

This device thereby provides a convenient means whereby a vibrator may be vehicle-mounted and rendered more able to move into resistive bodies.

This invention is not to be limited by the embodiments shown in the drawings and described in the description which are given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

I claim:

1. A vibrator system of adjustable rigidity, comprising: a vibrator having a fluid pressure inlet and an exhaust outlet; a handle; a coupling for mounting the vibrator to the handle, said handle, coupling and vibrator having coincidentlongitudinal axes, and the vibrator being adapted to exert unbalanced lateral vibratory forces, the coupling joining the vibrator and handle, and holding them in axially spaced-apart relationship, the coupling comprising an inherently flexible ball joint including a socket member having an internal socket and aball inside said socket, said socket and ball having coincident centers when the ball is axially centered in the socket, and a pair of peripheral pressure pads, one on each side of the center of the socket, and both extending around the coupling axis, each pad including a peripheral pressure groove, exhaust groove, and reference surface between the respective pressure and exhaust groove, the reference surface being separated by a spacing from the ball surface, said spacings being inversely related to each other as the ball shifts axially in the socket, and a pressure source discharging into each of the pressure grooves, the reference surfaces forming an inversely related pair of fluid restrictions tending to raise the pressure at one reference surface relative to the other, the resulting axially directed differential force on the coupling tend-ing to center the ball in the socket.

2. Apparatus according to claim 1 in which the pressure source comprises a constant-delivery pump delivering a constant and equal volume of fluid per unit time to each of the pressure grooves.

3. Apparatus according to claim 1 in which a respective orifice is placed in series fluid communication with each of the pressure grooves.

4. A vibrator system of adjustable rigidity, comprising: a vibrator having a fluid pressure inlet and an exhaust outlet; a handle; a coupling for mounting the vibrator to the handle, said handle, coupling and vibrator having coincident longitudinal axes, and the vibrator being adapted to exert unbalanced lateral vibratory forces, the coupling joining the vibrator and handle, and holding them in axially spaced-apart relationship; .axial thrust means adapted to exert an axial force on the vibrator to thrust it into an environment; and pressure means for varying the rigidity of the coupling as a function of the axial force exerted by the axial thrust means.

5. A vibrator system of adjustable rigidity, comprising: a vibrator having a fluid pressure inlet and an exhaust outlet; a handle, a coupling for mounting the vibrator to the handle, said handle, coupling and vibrator having coincident longitudinal axes, and the vibrator being adapted to exert unbalanced lateral vibratory forces, the coupling joining the vibrator and handle, and holding them in axially spaced-apart relationship, the coupling comprising an inherently flexible means; an axial thrust means adapted to thrust thevibrator axially; a pressure source; a pressure line connecting the pressure source to the fluid pressure inlet of the vibrator; an exhaust line which includes the flexible means, the pressure source comprising a constant-delivery pump; and means for adjusting the exhaust line pressure as a function of force exerted by the thrust means.

6. Apparatus according to claim 5 in which the axial thrust means comprises a piston-cylinder combination powered by a pressurized fluid, and in which said means for adjusting the exhaust line pressure is a pressure regulator which maintains in said exhaust line ,a pressure proportional to the thrusting pressure in the piston-cylinder combination.

7. Apparatus according to claim 4 in which the coupling comprises a flexible sleeve.

8. Apparatus according to claim 4 in which the coupling comprises a ball and socket joint.

9. Apparatus according to claim 5 in which the inherently flexible means comprises a flexible sleeve.

10. Apparatus according to claim 5 in which the inherently flexible means comprises a ball and socket joint.

References Cited by the Examiner UNITED STATES PATENTS 2/1939 Baily 259'l 9/1956 Fontaine 259'1 

5. A VIBRATOR SYSTEM OF ADJUSTABLE RIGIDITY, COMPRISING A VIBRATOR HAVING A FLUID PRESSURE INLET AND AN EXHAUST OUTLET; A HANDLE, A COUPLING FOR MOUNTING THE VIBRATOR TO THE HANDLE, SAID COUPLING AND VIBRATOR HAVING COINCIDENT LONGITUDINAL AXES, AND THE VIBRATOR BEING ADAPTED TO EXERT UNBALANCED LATERAL VIBRATORY FORCES, THE COUPLING JOINING THE VIBRATOR AND HANDLE, AND HOLDING THEN IN AXIALLY SPACED-APART RELATIONSHIP, THE COUPLING COMPRISING AN INHERENTLY FLEXIBLE MEANS 